Silica-based coating films are used in various applications, for example, interlayer insulating films in various elements, sealing materials in light-emitting devices such as LED devices and organic EL devices, coating films capable of diffusing impurity across semiconductor substrates, and gap-filling material for semiconductor processing. Such silica-based coating films are typically formed by applying a liquid composition containing a silicon-containing resin, such as a siloxane resin, to a substrate to form a coating film and then baking the resulting coating film.
As a coating-film-forming material for use to obtain silica-based coating films, a liquid composition containing a siloxane resin with a particular structure, silica with an average particle diameter ranging from 10 nm to 50 nm, and an organic solvent is known, for example (Patent Document 1).    Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2015-108087